WO2016166775A2

WO2016166775A2 - A device for groundwater iron removal and the process thereof

Info

Publication number: WO2016166775A2
Application number: PCT/IN2016/050112
Authority: WO
Inventors: Biswajit RUJ
Original assignee: Council of Scientific and Industrial Research CSIR
Current assignee: Council of Scientific and Industrial Research CSIR
Priority date: 2015-04-16
Filing date: 2016-04-18
Publication date: 2016-10-20
Anticipated expiration: 2017-10-16
Also published as: WO2016166775A3; WO2016166775A4

Abstract

Provision of an adequate supply of safe drinking water is a basic necessity for the wellbeing and socio-economic development. In the present invention groundwater contaminated with iron is manually pumped to the aeration chamber of the iron removal plant using water sprinkler through distribution plate and through force & lift arrangement. Holes are provided around the aeration chambers to facilitate maximum flow of ambient air for aerial oxidation. The user can instantly get iron-free potable clear water. Drain pipe, inlet pipe for back wash and back wash line at the bottom of the pre-settling chamber are provided for backwashing purpose.

Description

A device for groundwater iron removal and the process thereof

FIELD OF INVENTION

[0001] The present subject matter relates to waste water treatment and, particularly but not exclusively, to iron removal from groundwater.

BACKGROUND

[0002] Groundwater may be found at various depths at any location on Earth's surface. Groundwater is often considered as a safe source of drinking water than surface water because the groundwater generally does not contain harmful pathogens and may be used without any treatment.

BRIEF DESCRIPTION OF THE DRAWINGS

[0003] The detailed description is described with reference to the

accompanying figure(s). In the figure(s), the left-most digit(s) of a reference number identifies the figure in which the reference number first appears. The same numbers are used throughout the figure(s) to reference like features and components. Some embodiments of systems and/or methods in accordance with embodiments of the present subject matter are now described, by way of example only, and with reference to the accompanying figure(s), in which:

[0004] Figure 1 illustrates a general assembly of an iron removal plant, in accordance with an embodiment of the present subject matter.

[0005] Figure 2 illustrates sectional views of component A & B of improved iron removal plant, according to an embodiment of the present subject matter. DETAILED DESCRIPTION

[0006] Systems and methods for removing iron form a groundwater are described. About 96 percent of all unfrozen fresh water is found below the Earth's surface and is known as groundwater. Groundwater globally provides about 25 to 40 percent of the world's drinking water. However, with increased use of chemicals, contamination of groundwater has become a growing concern. For example, contamination occurs from highly visible sources, such as from landfills, gas stations, industry, and agriculture. Other potential contaminants may come from common everyday activities, such as septic systems, lawn and garden chemicals, pesticides, and fertilizers. When rainwater comes in contact with any source of contamination at the Earth's surface or in the soil, the rainwater carries such contaminants along with it to the groundwater.

[0007] Commonly occurring contaminants include iron, specifically in rural areas the groundwater may contain large quantities of iron. The presence of excess iron in ground water creates several problems including serious health hazards to the masses. Iron-bearing groundwater is often noticeably orange in colour, causing discoloration of laundry, and has an unpleasant taste, which is apparent in drinking and food preparation. As a result, people avoid usage of groundwater and return to drinking surface water.

[0008] As per United States Public Health Service (USPHS) drinking water standardsand Indian Standards (IS) code, the limit of iron content in drinking water is 0.3mg/L. Later, after considering physiological nutrition factor, the World Health Organisation (WHO) recommended the limit of iron for human consumption to 1.00 mg/L subject to economical and technical viabilities. However, the amount of iron in the groundwater is way more than the recommended limits. Current approaches for removing iron contaminants from groundwater have high operating costs and involve electrical power to run the compressor for supply of air. In addition, the current approaches involve chemically active filtration media. Further, backwashing of the filtration media is not provided to rejuvenate the media for prolonged use.

[0009] Accordingly, the present subject matter provides a system and a method for removing iron from groundwater. The present subject matter includes an iron removal plant which accommodates a force & lift type arrangement fitted with a hand pump, such as a Mark- II hand pump, for lifting the groundwater. The hand pump may be used to pump the groundwater to an aeration chamber. The aeration chamber is provided with a number of holes for maximum flow of air for oxidation of ferrous ion to ferric state that may be present in the groundwater. Further, the iron removal plant may include a pre-settling chamber to settle the iron precipitate. The water from the pre-settling chamber may be transferred to a settling chamber through a down flow pipe. The settling chamber may facilitate in settling entire iron precipitate in a filter media, such as a gravel bed, charcoal bed and a sand bed. Further, the iron removal plant may include an outlet tap to collect iron free water for the purpose of drinking.

[0010] In operation, groundwater contaminated with iron is manually pumped to the aeration chamber through force & lift arrangement. Further, the holes provided around the aeration chamber facilitate maximum flow of ambient air for aerial oxidation. Thereafter, the water is passed to the settling chamber through the down- flow pipe which is fixed vertically at the centre of the pre-settling chamber. In an implementation, a lower tip of the down-flow pipe is diagonally cut for free flow of water from pre-settling chamber to the settling chamber. Further, the pre-settling chamber is fixed at the top of the settling chamber by tightening the screws. At the settling chamber, after passing through gravel bed, charcoal bed, and the sand bed, iron free water is stored through up-flow at the top of sand bed. In the settling chamber, precipitated ferric ion (Fe+++) settles and the filtration is up-flow. Therefore, if any ferric ion moves along with the water, the same will be arrested by the filter media, thereby facilitating removal of iron. [0011] The user can instantly get iron free portable clear water. Further, the iron removal plant may be provided with a drain pipe, an inlet pipe and a back wash line at the bottom of the pre-settling chamber for backwashing purpose. In an example, the inlet pipe and the drain pipe may include a valve. During backwashing, the valves of the inlet pipe and the drain pipe are to be opened. If the water is continuously pumped, the water may pass through the inlet pipe and all precipitated iron will be removed through the drain pipe. The backwash line, as the name suggests, facilitates in backwashing, As the Fe+++ will also be precipitated in the pre-settling chamber, if the backwash line is kept open while pumping the water, the Fe+++ may be removed through the backwash line.

[0012] Accordingly, the present subject matter provides an iron removal plant for efficiently removing iron from groundwater without using any electrical power and chemicals with an optimum cost of production to ensure potable water. Further, the iron removal plant is cost-efficient, compact in design and may be operated by an unskilled person. The present subject matter facilitates in providing potable water simultaneously.

[0013] Figure 1 illustrates a general assembly of an iron removal plant 100, in accordance with an embodiment of the present subject matter. The iron removal plant 100 is attached to a hand pump 17, such as an Indian Mark-II hand pump, for pulling the groundwater and feeding into the iron removal plant 100. In an example, the groundwater is pulled by a force & lift type arrangement of the hand pump 17 for lifting the groundwater to the aeration chamber 02. The groundwater is supplied to the aeration chamber 02 through a water sprinkler 01 provided at a top portion of the aeration chamber 02. In an implementation, the aeration chamber 02 is provided with a plurality of holes 05 for facilitating maximum flow of ambient air into the aeration chamber 02. The plurality of holes 05 helps in oxidation of iron present in the groundwater. [0014] In the aeration chamber 02, the ambient air gets completely mixed with the groundwater resulting in aerated water. The aerated water is then made to pass through a plurality of gravel beds 03. It may be noted that the gravels which are being used in the present subject matter are naturally available gravel and no additional heat or chemical treatment is performed. The gravel beds 03 facilitate in conversion of ferrous iron (Fe⁺⁺) into ferric iron (Fe⁺⁺⁺). The gravel beds 03 provide time to the aerated water to get more oxidation, i.e., from the ferrous state to the ferric state. Basic principle is oxidising the Fe⁺⁺ of groundwater to Fe⁺⁺⁺ and removal of the Fe⁺⁺⁺ precipitates through settling and filtration.

Aerial oxidation of Fe⁺⁺ is as follows:

Fe⁺⁺ + (¼)0₂ + H⁺<→ Fe⁺⁺⁺ + (½)H₂0

[0015] Thereafter, the groundwater with ferric iron settles at the pre-settling chamber 04. The pre-settling chamber 04 facilitates in partial conversion of ferrous ion (Fe++) to ferric ion (Fe+++). This Fe+++ will be removed through the backwash line 14. The water slowly rises inside the pre-settling chamber 04 as the pumping is continued and then the water falls through the down pipe 11 into the settling chamber 09 at the bottom. The down pipe 11 is fixed vertically at the centre of the pre-settling chamber 04 and its lower tip is diagonally cut for free flow of water from the pre- settling chamber 04 to the settling chamber 09. In an example, the down pipe 11 facilitates in connecting the pre-settling chamber 04 with the settling chamber 09. Thus, to minimize the load of ferric ion settled in the settling chamber 09, the pre- settling chamber 04 is provided in the iron removal plant 100. In the absence of the pre-settling chamber 04, the settling chamber 09 may get choked and may have to be backwashed at a frequent basis.

[0016] Further, the water gradually rises in the settling chamber 09 and passes through different filter media, such as the sand bed 06, the charcoal bed 07, and the gravel bed 08. This water initially passes through the gravel bed 08 and subsequently passes through charcoal bed 07 and a sand bed 06. It may be noted that the gravel bed 08 and the gravel bed 03 perform different functions in the iron removal plant 100. For example, the gravel bed 03 facilitates in oxidation of Fe++ to Fe+++ state as the gravel bed 03 covers more area of the groundwater. The gravel bed 08 includes gravels of smaller size as compared to the gravels of the gravel bed 03. Therefore, the gravel bed 08 facilitates in arresting the ferric ions.

[0017] In an implementation, the charcoal bed 07 is placed in-between the gravel bed 08 and sand bed 06 for removing odor of water, if any. Thereafter, the iron free water is stored at the top of sand bed 06. The user can instantly get iron free potable clear water 13 even without pumping for sometimes. Further, the settling chamber 09 is provided with a flange manhole 12 for replacing or changing the filter media. For example, after certain period of time, efficiency of the iron removal plant 100 may get reduced even after backwashing of the settling chamber 09. In such a scenario, the filter media has to be changed by opening the flange manhole 12.

[0018] In case of non-functioning of the plant, IM-II hand pump water can be used for other purpose other than drinking by opening the valve 16 and this water can also be used for collection of raw water (iron contaminated) for testing purpose to know the concentration of iron of the groundwater.

[0019] In this present system, the pre-settling chamber 04 is fixed at the top of the settling chamber 09 by tightening the screws which are located at places around the section/part (B) as shown in the drawing in Fig.2. So, it is easy to transport as the system can be separated.

[0020] The present subject matter facilitates in delivering iron free safe drinking water. The iron removal plant includes a plurality of holes around the aeration chamber thereby, providing double aeration and proper air flow. This leads to the oxidation of ferrous iron to the ferric state. The pre-settling chamber along with the settling chamber leads to increase in removal efficiency of the iron removal plant. Quick delivery with no time. When the filter media is heavily choked, the filter media may be backwashed to rejuvenate the filter media for prolonged use.

[0021] The present subject matter also provides a flange manhole in the settling chamber to change the filter media when the filter is not working satisfactorily. Thereby facilitating the iron removal plant to maintain the quality of the potable water after each use.

[0022] The following example is given by way of illustration of the working of the invention in actual practice and therefore should not be construed to limit the scope of the present invention.

EXAMPLE

Improved Iron Removal Plant data

[0023] It can be concluded from the above example that the provision of double aeration chamber with proper air flow and pre-settling chamber along with the settling chamber ensure the desired amount iron concentration by complete

precipitation and removal of excess iron from the ground water. It is also observed that the improved iron removal plant could remove the groundwater iron concentration from 17 mg/L to 0.2 mg/L.

[0024] Accordingly, the iron removal plant of the present subject matter is compact, requires less space and easy to manufacture. The iron removal plant involves no running cost and provides uniform oxidation in the aeration chamber by means of the equally spaced holes around the aeration chamber.

Claims

We claim:

1. A device (100) for removing iron from groundwater, the device (100) comprising:

an aeration chamber (02);

a distribution plate (01) provided at a top portion of the aeration chamber (02); a pre-settling chamber (04) attached to a bottom portion of the aeration chamber (02), wherein the pre-settling chamber (04) allows initial settlement of the groundwater;

a settling chamber (09) connected to the pre-settling chamber (04), a down pipe (11), a filter media (06, 07, 08), a back-washing provision (05, 10 and 14); and a provision for change of filter media (12).

2. The device (100) as claimed in claim 1, wherein a hand pump is fitted with the iron removal plant for removal of excess iron from ground water.

3. The device (100) as claimed in claims 1-2, wherein the aeration chamber (02) is provided with a water sprinkler through the distribution plate (01) to oxidize Fe⁺² ions soluble in the groundwater.

4. The device (100) as claimed in claims 1-3, wherein a plurality of holes (05) is provided around the aeration chamber (02) to allow maximum flow of ambient air within the aeration chamber (02).

5. The device (100) as claimed in claims 1-4, wherein the pre-settling chamber (04) comprises a gravels bed (03).

6. The device (100) as claimed in claims 1-5, wherein the gravel bed (03) is provided to arrest the Fe⁺³ precipitate.

7. The device (100) as claimed in claims 1-5, wherein the down pipe (11) is fixed vertically at the centre of the iron removal plant to fall through the water into the settling chamber

(09) at the bottom.

8. The device (100) as claimed in claims 1-6, wherein a lower tip of the down pipe (11) is diagonally cut for free flow of water from the pre-settling chamber (04) to the settling chamber (09).

9. The device (100) as claimed in claim 1, wherein the filter media (06, 07, 08) comprises a sand bed (06), a charcoal bed (07) and a gravels bed (08).

10. The device (100) as claimed in claim 9, wherein the charcoal bed (07) is provided in- between the gravel bed (08) and the sand bed (06) to remove any odor from water.

11. The device (100) as claimed in claim 1, wherein the pre-settling chamber (04) is fixed at the top of the settling chamber (09) by tightening the screws which are located at places around the section/part (B).

12. A process for iron removal from groundwater, the process comprising:

feeding pumped ground water to an aeration chamber (02) using water sprinkler through a distribution plate (01);

passing the aerated water through a gravel bed (03) to fall into a settling chamber (09) at a bottom through a down pipe (11);

passing the water through a filter media (06) to get iron free water; and collecting the iron free water through an outlet tap.